This invention relates generally to a sensing system for detecting adverse weather conditions which are hazardous to flying aircraft and more particularly to a sensor for optically characterizing ring-eddy atmospheric turbulence emanating sound (SOCRATES) produced by aviation hazards such as clear air turbulence, windshears, microbursts, and aircraft generated wake vortices, all of which at some time or another have proved to be hazardous to aircraft and its passengers. The information gathered by the system provides early warning to pilots or ground based personnel.
In the past various proposals have been offered to provide information regarding hazardous weather conditions to airborne pilots or to ground based personnel and some of those proposals have included laser detection devices which sense such atmospheric conditions as temperature, water vapor content, and air velocity as indicators of weather conditions. None of these prior laser based systems has been widely accepted commercially.
Other types of detection systems such as weather-SODAR (Sound Detection and Ranging) and weather-radar have been used but these systems do not provide an all weather capability because they measure weather conditions in such a way that they experience reduced energy backscattering under the very turbulent mixing of air masses they are trying to detect. Consequently these systems have a tendency to fade away during bad weather conditions at a time when they are needed most. Similarly, weather lidar systems, although more accurate than weather radar, are known to be less weather tolerant than their radar counterpart.
Consequently there is a need for greater airline safety due to recent aviation catastrophes or near disasters whose causes remain unexplained or attributable to clear air turbulence, wake vortices, windshears, and microbursts.
Since about the 1970's, it has been recognized that these atmospheric phenomena contain or generate acoustic patterns or signatures in the form of very low frequency sound waves which travel over long distances relatively unimpeded by the surrounding weather or other atmospheric phenomena. This sound generation phenomena, known as ring-eddy vortexing and its associated velocity circulation and unsteady flow fields, essentially create radiated sound which resembles the wave patterns occurring in a body of water after a pebble has been tossed into it. The rings created by the pebble intrusion are similar in shape to the acoustic patterns associated with severe thunderstorms, wake vortices and other clear air turbulence.
It has also been publicly known since about the 1970's that moving objects such as ships, submarines or animals in water generate and radiate sound waves which may be detected by a laser sensing system utilizing free space or wave guided light beams to indicate the presence and location of those sound radiating or reflecting objects in the water. One such system is illustrated in Jacobs U.S. Pat. No. 5,504,719.
However, despite this prior public knowledge, no one has suggested or successfully implemented a laser detection system responsive to sound waves produced by adverse and hazardous weather or wake-vortex conditions to provide an advance warning of those conditions to aircraft pilots or airport ground personnel.
The SOCRATES system of the invention is intended to do just that.